Alloy.



. tionable,

which. is so resistant istics make it of UNITED STATES PATENT OFFICE.

w. rum, or We, nmnors.

To all whom it may concern:

Be it known that I SAMUEL a citizen of the United States, at Urbana inthe county of Champaagn and State of Illinois, have made new and usefulImprovements in lowing (being in part a continuation of my applicationSerial No. 7 05,386, filed June 24, 1912) is a specification.

Bomb calorimeters asvordinarly used are constructed of steel with theinner faces lined with platinum or with gold plated cop per to resistthe corrosive action ofthe m tric acid liberated in the calorimeter whenin use. Such constructions have the dlsadvanta'geof high cost, and alsothe disadvantage that moisture may work 1n under the lining andsubsequently impair the accuracy of the heatdetermination. Also platinumlinings as thus used within a calorimeter are easily damaged and. areotherwlse ob ecas is well known,

As the result of extended experiment and investigation I have discovereda new alloy to the corrosive action of the moist oxygen or of ordinaryacids such as nitric acid that it-can beused within the calorimeter andexposed directly to the action of the calorimeter charge. The alloy isso resistant that it may be used for valve seats, and similar arts ofthe apparatus where the wear an exposure are extreme, withoutappreciable corrosion or deterioration even after long continued use.This alloy is also adapted for use in the construction of chemicalvessels, and as electric resistance wire and as a substitute forplatinum and other expensive materials and in the form of a wire orsheet metal suitably shaped and worked, may be used in a great varietyof ways, where its specialcharacterspecial value in the technical arts.In general this new alloy comprises nickel .as its basis, together witha certain amount of chromium or of molybdenum or of both and a somewhatsmaller quantity of copper. The chromiumaccentuates the acid resistingproperties of the nickel, and tends to increase the melting temperatureand also leads: to brittleness. The copper on the other hand tends tolower the meltlng point, but it cannot be used except in moderatequantity withoutlowering the resistance to corrosion. I have found thatAlloys, of which the fol- AIJIHL 1,115,239. W Patented Oct. 2'7, 1914. aNo Drawing. Application fled Iebmaryii' l, 1914;- serial No. 821,593.

there is also advantage in having tungsten present. and while itspresence may not be necessary, yet it tends toward easy casting and alsostrengt'hens the acid resisting properties of the alloy. Molybdenum maybe used .in place of tungsten to a very considerable extent with someresultant advantages. Tungsten'is much like chromium in promotingresistance to acid attack, but it is quite in contrast with chromium inthat it permits easy casting and reduces shrinkage. Aluminum andmanganese in' small quantities can also be used to advantage it is aboutin condition for pouring. Aluminum lowers the melting point of the alloysomewhat and besides eing a good deoxidizer, it accentuates theresistance to both nitric and sulfuric acid. Manganese serves much asaluminum. Titanium and boron in fractional percentages may also be used.

I have found that the relative proportion of the elements above namedmay be varied through relatively wide limits and still yield an alloyhaving, in the main, the mechanical strength and tou hness and the acidresisting characteristics 0 metal suitable for use in calorimeters, andas electricalresist ances, and in the arts generally. I have found thatthe following composition by weight gives good results: 63 parts nickel,5 parts copper, 15 parts chromium, 10 parts of molybdenum-chromium alloyin equal percentages, 2 parts tungsten, 11} parts aluminum, 1% partsmanganese-titanium alloy compounded in the proportions of 7 0 partsmanganese to 30 parts titanium, 1 part man-. ganese-boron alloycompounded in the proportion 70 parts manganese to 30 parts boron,'1'part copper-silicon alloy compounded in the proportions 80 parts copperto 20 parts silicon, part boron suboxid (approximately B 0). As tovariations from the above proportions, I have found that the nickelcontent may vary between 55 and 65 per cent, and the copper between 5and 11 per cent. As tothe members of the chromiumgroup, viz.,' chromium,molybdenum and tungsten, these metals are to some extentinterchangeable, but preferably should total in the neighborhood of 27per cent. Molybdenum, in its behavior, seems more pronounced thantungsten in promoting resistivity to acid, and may vary from being addedafter the mass is fluid and when 5 to. 8 per cent. The chromium contentmay vary between 15'and 21 per cent, the tungsten between about 2 and 3'per cent., and,

the aluminum between i; and 15 per cent. The manganese and titanium maybe omit ted altogether, although I regard'them as substantial aids incasting and as desirable deoxidizers. The boron and boron suboxid canalso be omitted, their principal functions being that of a flux anddegasifier, but if any boron remains behind in the alloy it'ofi'ers nodisadvantage and may even present some advantages. Silicon also beomitted. npractic'e I prefer to melt together in about the proportionabove indicated, the nickel, chromium, molybdenumchromium alloy, copperand tungsten, and then after the melt is fluid, I add the aluminum,man-' ganese-titanium alloy, manganese-boron alloy and copper-siliconalloy in about the proportions stated, these additions serving to removegases and increase the fluidity of the melt and otherwise assisting inbrlnging the fnaterial into better physical and 4 chemical condition forpouring. Finally I add the one-half per cent. suboxid and this acts toeliminate absorbed gases and to deoxidize the other metals.

In some melts I have omitted both the coppersil'icon alloy and the boronflux and stillobtained a satisfactory product and I am aware that themanganese may be omitpresent without harm, say of 1 per cent.

The best melting and casting temperature for the alloy here disclosed,in its various modifications, is in the neighborhood of 1300 degreescentigrade with 1500 degrees centigrade as the upper limit.

- The alloy may be cast in iron molds not heated, or in sand, and whenthus made has a tensile strength of about 55,000 to 60,000 pounds persquare inch. The cast material can be rolled and drawn into wire and canbe spun and mechanically worked according to well known metal workingmethods. With drawn wire, the tensile strength is much greater than thatgiven for the cast material, being in the neighborhood of 124,000 poundsper square inch in some cases. The relatively great strength andtoughness of the alloy even in cast con- .sential; The electricalresistance of the alloy is high, being in the neighborhood of ti tytimes that of copper. The melting point is in the neighborhood of 1200to 1300 degrees centigrad The material, either in cast, rolled or drawncondition is non-oxidizable in the ordinary sense. Corrosion, 'if itoccurs at all, at atmospheric temperature and pressure, when 100 squarecentimeters area is subjected for twenty-four hours to four. timesnormal HNO or H 80 or mixtures of these acids, is so slight as to besubstantially within the experimental error of weighing, even thoughthebalance used may show changes of one-tenth of a milligram. Samples ofabout ten square centimeter area have been exposed for as long astendays to 25 per cent. nitric acid with no loss in weight which couldbe detected by the most accurate weighing With other samples under thesame conditions, there was a loss of .002 mil-.

ligrams per square centimeters per hour in 25 percent. nitric acid andfor practical purposes this may be regarded as no corrosion.

The alloy is equally insoluble-in 25 per cent. H 80; or in a 25 percent. mixture of two parts sulfuric acid to one part nitric acid. In 25perqcent. hydrochloric acid, the corrosion is possibly twice as high asin nitric (for such samples as show any corro-.

sion in nitric), and consequently even with hydrochloric, the materialmay be said 'to be non-corrosive. 1

As the result of the continued use of the alloy here disclosed, forexposed surfaces in a bomb calorimeter of the construction disclosed inany application above identified,

where the alloy is directly in contact with the hot gases, it may besaid that the total corrosion within the bomb, under the extremetemperatures and pressures there en countered, need not exceed 6 foreach heat, and such a slight corrosion, assuming that it might takeplace, would in-' troduce a variable of not more than 1 part in 10,000which of course, is well within the experimental accuracy of methods forusing bomb calorimeters.

In addition "to the use of this alloy for bomb calorimeters and forvalves, valve seats and exposed portions of chemical vessels, it has awide range of uses in the electrical and mechanical arts where itsspecial of a milligram toughness, high electrical resistance and moreparticularly its resistance to oxidation or corrosion, can be made useof.

I claim:

1. A non-oxidizing alloy having a composition of about 63 parts nickel,5 parts co per, 20 parts chromium, 5 parts molybd dnum, and 2 partstungsten.

2. A non-oxidizing alloy consisting of ap. proximately 63 parts nickel,5 parts copper, 20 parts chromium, 5 parts molybdenum, 2 parts tungsten,and a small percentage oi? deoxidizing material substantially as described.

3. A non-oxidizing alloy having a composition of about 63 parts nickel,5 parts copper and 27 parts metal of the chromium group, with a smallpercentage of deoxidizing metal, substantially as described.

4. An alloy having a composition of about 63% nickel, 5% copper, 20%chromium, 5% molybdenum, 2% tungsten and less than 2% each of aluminum,manganese and boron, substantially as described.

5. An alloy of about the composition 63% nickel, 5% copper, and 27%metal of the chromium group, said alloy being characterized by a highelectrical resistance, by high resistance to corrosion, and by a tensilestrength for unworked metal in the neighborhood of 60,000 pounds persquare inch, substantially as described.

I In testimony whereof I aflix my signature, in presence of twowitnesses.

SAMUEL W. FARR. Witnesses:

F. W. BECK, F. H. BARTON.

